Effect of complex nucleating agents on crystallization behavior of CaO–Al2O3–SiO2–ZnO–Na2O–K2O glass-ceramics

Single (TiO₂) and complex (TiO₂ and ZrO₂) nucleating agents were added in CaO–Al₂O₃–SiO₂–ZnO–Na₂O–K₂O-based multicomponent glass to investigate its crystallization behavior and physical properties according to the types and amounts of nucleating agents. Nonisothermal analysis revealed crystallization behavior with an activation energy (E) of 165.176–518.985 kJ/mol and Avrami constant (n) of .73–2.12 with the complex nucleating agent. X-ray diffraction was used to observe the titanite and zircon crystalline phases in glass when using complex nucleating agents, and the crystallinity was found to be 43%–55%. Scanning electron microscopy and energy-dispersive x-ray spectroscopy were used to observe the plate-shaped titanite and column-shaped zircon crystalline phase in the glass matrix, and the glossiness was found to be decreased owing to the crystallization of the glass. The glass-ceramic showed a higher hardness and fracture toughness value of 6.45–6.7 GPa and 1.54–3.35 MPa∙m^1/2 when using the complex nucleating agent rather than when using the single nucleating agent.